Monsters escape from Hell to harvest human spirits, attracted by the tainted minds of people. To reach the human world, they break the rules. When Tsutomu, a student at Yokai Elementary School, is suddenly attacked by these monsters, he is rescued by Enma‑kun, the son of Enma, along with Yukiko, a snow woman, and Kapaeru. The trio are members of the Monster Patrol, a group dispatched to the human world to apprehend monsters.